Use fixed toolchain

.github/workflows/ci.yml

@@ -32,10 +32,7 @@ jobs:
           distribution: 'temurin'
           java-version: '11'
       - name: Install Rust
-        uses: actions-rs/toolchain@v1
-        with:
-          toolchain: stable
-          override: true          
+        uses: dtolnay/[email protected]
       - name: Check Formatting
         run: cargo fmt -- --check
       - uses: actions/setup-python@v5